On Sat, Aug 24, 2013 at 01:55:38PM +0200, Jeroen Hofstee wrote:
The movt/movw instruction can be used to hardcode an memory location in the instruction itself. The linker starts complaining about this if the compiler decides to do so: "relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not be used" and it is not support by U-boot as well. Prevent their use by requiring word relocations. This allows u-boot to be build at other optimalization levels then -Os.
Signed-off-by: Jeroen Hofstee jeroen@myspectrum.nl Cc: TigerLiu@viatech.com.cn Cc: Albert ARIBAUD albert.u.boot@aribaud.net
arch/arm/config.mk | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
Is this also something we need for llvm? I am hesitant here because as Wolfgang points out, -O0 is usually the wrong way to debug a problem and I'll add we're well into the age where debuggers work just fine with optimized code. If there's some -O2 enabled gcc flag we want because of a measurable performance win, we should add it specifically to -Os.